BIOL 222 Lecture Notes - Lecture 28: X-Inactivation, Royal Jelly, Riboflavin
19 Nov 2016
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Lecture #28: eukaryotic gene regulation by chromatin structure, Outline: how do nucleosomes function in eukaryotic gene regulation, how does dna methylation regulate gene expression rates, how doe sepigentics work. Chromatin and gene regulation: chromatin = dna + proteins, closed vs open chromatin conformation. Closed = not accessible: closing and opening is a dynamic process. Chromatin remodeling: chromatin remodeling = chromatin structure can change from open to closed, is atp dependent, examples of chromatin remodeling proteins = swi/snf, iswi, ino80, mi-2, three main mechanisms for chromatin remodeling. 1. nucleosome repositioning: atp-dependent chromatin remodeling complex. In order to be tightly wound, must have energy to hold it together. The nucleosomes can be spaced evenly, or spaced un-evenly. 2. histone eviction (removal: when a histone is removed so a strand of dna is now exposed/open and free for replication. 3. histone variants: variations in histone can promote transcription. Ex. histones that are easier to transcribe the dna with.
